I know in the Slantnose, F-150's had the option of a LS front diff. We had one in an 83 F-150 4x4 351/C6. It had LS front and rear. It was a farmers truck before we bought it in 86. It must have had 4:10's also.... it could pull a house, but would not top 80 on the floor.
There was a learning curve to driving it in the snow on-road. We lived in the country and the roads, even after being cleared still had a layer of ice and snow on them. They were really crowned roads, and when you came to a stop, when you hit the gas, it would slide straight sideways until the right side was in the soft stuff on the side of the road, and it would take off.... was a great truck....... till it lost a wrist pin......
